While the internal combustion engine has been in existance for many years, its operating efficiency was of very little concern until the advent of the fuel shortage brought about by the Arabs in 1973. With this, the Environmental Protection Agency (EPA) was brought into full bloom as a necessary and operating part of our government. The public then had an awareness of the inefficiency of many of our mass produced energy consuming products. The need for more efficient automobile engines was very apparent, as was the environmental contamination which the automobile was creating because of its poor efficiency. Although the automotive industry has spent billions of dollars in an attempt to resolve the engine fuel efficiency problem, they have elected to downsize vehicles and engines. In so doing, safety and comfort have been sacrificed. The legislated Corporate Average Fuel Economuy (CAFE) standards are not being adhered to, even though "Ward's Automotive Reports", indicate that for the 1985 model year, over one-half of the cars built in the United States had small engines.
If we were to go to the root of the problem, we will have to examine the operation of the carburetor and the fuel injection systems that are currently being sold. We can observe that a carburetor delivers metered quantities of vaporized liquid fuel in the form of a spray having a wide variety of droplet sizes. As the spray moves through the manifold, the smaller low inertia droplets divide and become air-borne and follow the air currents in the manifold, while the larger and heavier droplets tend to travel in a substantially straight line. Thus, the larger droplets are unable to negotiate curves and are deposited on the inner surface of the mainfold. This method of liquid fuel vaporization leaves a great deal to be desired. Under the best of conditions, an internal combustion engine uses only a little over twenty five percent (25%+) of the energy in a gallon of gasoline. During ordinary driving in the city or during the winter, it may be even less than ten percent (10%-), which is better than most other ways of producing power.
To improve power output, throttle body and multi-port electronic fuel injectors have been developed and are now commercially available. Although the fuel injectors are more efficient than the carburetors in the delivery of minute vaporized liquid droplets in higher quantity, fuel vaporization still remains a serious problem and hampers the devolvement of more economical and efficient engines.
In reference to the above, if an internal combustion engine were to receive a perfect evaporated gaseous state fuel mixture, wherein the gaseous state fuel was uniformly mixed and distributed throughout the induction air, the resulting combustion would probably have a lower compression temperature, a reduced tendency to knock, as well as a higher volumetric efficiency. This is true because air would not be displaced by vaporized liquid fuel droplets on the intake stroke of the engine. Additionally, the evaporated gaseous state fuel/air mixture would tend to remain homogeneous while turning corners in the mainfold, thus eliminating collisions with and condensation on the inner surfaces of the manifold. This condition exists when liquid fuel is inadequately vaporized. It must also be remembered that the large, high inertia droplets of unvaporized liquid the large, high inertia droplets of unvaporized liquid fuel are basically non-combustible, with the result that they may be exhausted from the tailpipe. The unvaporized liquid fuel may also find its way into the crankcase, where it will dilute the lubricating oil and reduce its lubricity. It is possible that some of the liquid fuel may burn to some degree, leaving gum, varnish and hard carbon deposits throughout the engine. This of course is very detrimental to very efficient engine operation. Additionally, if the fuel air ratio is leaned a small amount, a reduction in exhaust gases occurs, because most of the HC and CO will be burned within the combustion chamber. This will reduce the temperature problem in the exhaust manifold, where the excess liquid fuel and gases are usually consumed. This being the case, the NO.sub.x emissions will also be reduced. It will also be noted that production electronic fuel injection systems are now available from a number of both domestic and foreign manufacturers, and with proper revision and adjustment, the engines fuel system can be electronically operated in several modes to obtain maximum fuel efficiency under all operating conditions.
The following description delineates a new method and apparatus for improving the fuel economy of an internal combustion engine by maximization of liquid fuel vaporization. This will operate to minimize the vaporization problems that are normally encountered when using a carburetor and/or an electronically controlled liquid fuel metering and vaporizing injector system, although one of the above identified and described fuel delivery systems may be used in conjunction with the evaporated gaseous state fuel delivery system that is taught in the accompanying specification and appended claims. The proposed, new and unique dual state fuel delivery system will not only extend the working life of the fuel system and engine, it will also reduce the cost of engine maintenance at the same time.